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        <item>
            <title>Review Exercise 2 (Solutions)</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/rev-ex</link>
            <description>Review Exercise 2 (Solutions)

The solutions of the Review Exercise 2 of book “Model Textbook of Mathematics for Class XI” published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan are given on this page. This exercise consists of the MCQs and question all topics included in this chapter.$A$$m \times n$$B$$n \times p$$A B$$n \times p$$m \times p$$p \times m$$n \times n$$A$$1 \times n$$A^{t} A$$1 \times n$$n \times 1$$1 \times 1$$n \times n$$a_{i j}$$A$$a_{i j}=(-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 08 Feb 2026 16:57:09 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Exercise 2.6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-6-p1</link>
            <description>Question 1, Exercise 2.6

Solutions of Question 1 of Exercise 2.6 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $ 2 x_{1}-3 x_{2}+4 x_{3}=0$$x_{1}-2 x_{2}+3 x_{3}=0$$4 x_{1}+x_{2}-6 x_{3}=0$\begin{align*}
&amp;2 x_{1}-3 x_{2}+4 x_{3}=0\cdots (i)\\
&amp;x_{1}-2 x_{2}+3 x_{3}=0\cdots (ii)\\
&amp;4 x_{1}+x_{2}-6 x_{3}=0\cdots (iii)\\
\end{align*}\begin{align*}
A &amp;= \le…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:03:49 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 and 8, Exercise 2.6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-6-p7</link>
            <description>Question 7 and 8, Exercise 2.6

Solutions of Question 7 and 8 of Exercise 2.6 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[\begin{array}{ccc}3 &amp; 2 &amp; 1 \\ 4 &amp; -1 &amp; 2 \\ 7 &amp; 3 &amp; -3\end{array}\right]$$A^{-1}$$3 x+4 y+7 z=14 ; 2 x-y+3 z=4 ; \quad x+2 y-3 z=0$\begin{align*}
A &amp;= \begin{bmatrix}
3 &amp; 2 &amp; 1 \\
4 &amp; -1 &amp; 2 \\
7 &amp; 3 &amp; -3
\end{bmatrix}\\
|…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:13:32 +0000</pubDate>
        </item>
        <item>
            <title>Exercise 2.1 (Solutions)</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-1</link>
            <description>Exercise 2.1 (Solutions)

The solutions of the Exercise 2.1 of book “Model Textbook of Mathematics for Class XI” published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan are given on this page. This exercise consists of the question related to order, different type of matrices and transpose of matrix.$A=\left[\begin{array}{lll}1 &amp; 3 &amp; 0 \\ 2 &amp; 0 &amp; 1\end{array}\right]$$B=\left[\begin{array}{ll}1 &amp; 2 \\ 2 &amp; 3 \\ 3 &amp; 4\end{array}\right]$$C=\left[\begin{array}{l}1 \…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 08 Feb 2026 16:35:15 +0000</pubDate>
        </item>
        <item>
            <title>Exercise 2.2 (Solutions)</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2</link>
            <description>Exercise 2.2 (Solutions)

The solutions of the Exercise 2.2 of book “Model Textbook of Mathematics for Class XI” published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan are given on this page. This exercise consists of the question related to sum, product and different operations on matrices.$A=\left[a_{i j}\right]$$2 \times 2$$a_{i j}=\dfrac{i+3 j}{2}$$a_{i j}=\dfrac{i \times l}{2}$$a_{i j}=\dfrac{i}{j}$$a_{i j}=\dfrac{2 i-3 j}{3}$$B=\left[a_{\ell}\right]$$3 \…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 08 Feb 2026 16:40:19 +0000</pubDate>
        </item>
        <item>
            <title>Exercise 2.3 (Solutions)</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-3</link>
            <description>Exercise 2.3 (Solutions)

The solutions of the Exercise 2.3 of book “Model Textbook of Mathematics for Class XI” published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan are given on this page. This exercise consists of the question related to determinant and inverse of the matrix.$\left[\begin{array}{ccc}2 &amp; 3 &amp; 1 \\ 1 &amp; -1 &amp; 2 \\ 4 &amp; 1 &amp; 2\end{array}\right]$$\left[\begin{array}{ccc}\cos \theta &amp; -\sin \theta &amp; 0 \\ \sin \theta &amp; \cos \theta &amp; 0 \\ 0 &amp; 0 &amp; 1\en…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 08 Feb 2026 16:44:16 +0000</pubDate>
        </item>
        <item>
            <title>Exercise 2.4 (Solutions)</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-4</link>
            <description>Exercise 2.4 (Solutions)

The solutions of the Exercise 2.4 of book “Model Textbook of Mathematics for Class XI” published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan are given on this page. This exercise consists of the question related to the determinant and properties of the determinant.$\left|\begin{array}{lll}9 &amp; 27 &amp; 36 \\ 18 &amp; 54 &amp; 24 \\ 27 &amp; 81 &amp; 28\end{array}\right|=0$$\left|\begin{array}{lll}1 / a &amp; b c &amp; b+c \\ 1 / b &amp; a c &amp; a+c \\ 1 / c &amp; a b &amp; a+…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 08 Feb 2026 16:46:40 +0000</pubDate>
        </item>
        <item>
            <title>Exercise 2.5 (Solutions)</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-5</link>
            <description>Exercise 2.5 (Solutions)

The solutions of the Exercise 2.5 of book “Model Textbook of Mathematics for Class XI” published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan are given on this page. This exercise consists of the question related to solving system of the equation of three variables by using matrices.$\left[\begin{array}{ccc}1 &amp; 3 &amp; 5 \\ -6 &amp; 8 &amp; 3 \\ -4 &amp; 6 &amp; 5\end{array}\right]$$\left[\begin{array}{ll}2 &amp; 1 \\ 3 &amp; 2 \\ 1 &amp; 9\end{array}\right]$$\left[…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 08 Feb 2026 16:50:14 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Review Exercise</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/re-ex-p1</link>
            <description>Question 1, Review Exercise

Solutions of Question 1 of Review Exercise of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A$$m \times n$$B$$n \times p$$A B$$n \times p$$m \times p$$p \times m$$n \times n$$m \times p$$A$$1 \times n$$A^{t} A$$1 \times n$$n \times 1$$1 \times 1$$n \times n$$n \times n$$a_{i j}$$A$$a_{i j}=(-1)^{i+j} A_{i j}$$a_{i j}=(-1)^{i+j}…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 25 Nov 2024 17:51:01 +0000</pubDate>
        </item>
        <item>
            <title>Question 4 and 5, Review Exercise</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/re-ex-p3</link>
            <description>Question 4 and 5, Review Exercise

Solutions of Question 4 and 5 of Review Exercise of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\left|\begin{array}{ccc}a+1 &amp; l &amp; l \\ l &amp; a+1 &amp; l \\ l &amp; l &amp; a+1\end{array}\right|=(a+1+2 l)(a+1-l)^{2}$\begin{align*}
L.H.S &amp;= \left|\begin{array}{ccc}a+1 &amp; l &amp; l \\ l &amp; a+1 &amp; l \\ l &amp; l &amp; a+1\end{array}\right|\\
&amp;=\left|\b…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:15:45 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Exercise 2.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-1-p1</link>
            <description>Question 1, Exercise 2.1

Solutions of Question 1 of Exercise 2.1 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[\begin{array}{lll}1 &amp; 3 &amp; 0 \\ 2 &amp; 0 &amp; 1\end{array}\right]$\begin{align}\text{Order of A}&amp;= 2\times 3\end{align}$B=\left[\begin{array}{ll}1 &amp; 2 \\ 2 &amp; 3 \\ 3 &amp; 4\end{array}\right]$\begin{align}\text{Order of B}&amp;= 3\times 2\end{align}$C…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 27 Jul 2024 09:35:52 +0000</pubDate>
        </item>
        <item>
            <title>Question 2, Exercise 2.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-1-p2</link>
            <description>Question 2, Exercise 2.1

Solutions of Question 2 of Exercise 2.1 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\quad A=\left[\begin{array}{lll}3 &amp; 6 &amp; 2 \\ 2 &amp; 1 &amp; 9\end{array}\right]$$B=\left[\begin{array}{ll}\frac{1}{3} &amp; 1 \\ 2 &amp; 6\end{array}\right]$$C=\left[\begin{array}{l}3 \\ 2 \\ 8\end{array}\right]$$D=\left[\begin{array}{lll}1 &amp; 6 &amp; 9 \\ 2 &amp; 0 …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 27 Jul 2024 09:36:13 +0000</pubDate>
        </item>
        <item>
            <title>Question 3, Exercise 2.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-1-p3</link>
            <description>Question 3, Exercise 2.1

Solutions of Question 3 of Exercise 2.1 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $$A=\begin{bmatrix}
3 &amp; 0 &amp; 0 \\
0 &amp; 1 &amp; 0 \\
2 &amp; 6 &amp; 0
\end{bmatrix}$$$$B=\begin{bmatrix}
-6 &amp; 0 &amp; 0 \\
0 &amp; -6 &amp; 0 \\
0 &amp; 0 &amp; -6
\end{bmatrix}$$$$C=\begin{bmatrix}
1 &amp; 0 \\
2 &amp; 0
\end{bmatrix}$$$$D=\begin{bmatrix}
1 &amp; 0 &amp; 0 \\
0 &amp; 1 &amp; 0 \\
0 &amp;…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 27 Jul 2024 09:36:33 +0000</pubDate>
        </item>
        <item>
            <title>Question 4, Exercise 2.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-1-p4</link>
            <description>Question 4, Exercise 2.1

Solutions of Question 4 of Exercise 2.1 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $$
A=\left[\begin{array}{ccc}
2 &amp; 0 \\
\sqrt{5} &amp; 6 \\
1 &amp; 9
\end{array}\right]$$$$
A^t=\begin{bmatrix}
2 &amp; \sqrt{5} &amp; 1 \\
0 &amp; 6 &amp; 9
\end{bmatrix}$$$$B=\left[\begin{array}{cccc}
1 &amp; 6 &amp; 2 &amp; 0
\end{array}\right] $$$$B^t=\left[\begin{array}{c}
1…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 27 Jul 2024 09:36:55 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p1</link>
            <description>Question 1, Exercise 2.2

Solutions of Question 1 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[a_{i j}\right]$$2 \times 2$$a_{i j}=\dfrac{i+3 j}{2}$\( a_{ij} = \dfrac{i + 3j}{2} \)\( i = 1, j = 1 \)\[
a_{11} = \dfrac{1 + 3 \cdot 1}{2} = \dfrac{1 + 3}{2} = \dfrac{4}{2} = 2
\]\( i = 1, j = 2 \)\[
a_{12} = \dfrac{1 + 3 \cdot 2}{2} …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Tue, 30 Jul 2024 07:26:46 +0000</pubDate>
        </item>
        <item>
            <title>Question 3, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p2</link>
            <description>Question 3, Exercise 2.2

Solutions of Question 3 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[\begin{array}{ccc}3 &amp; -1 &amp; 2 \\ 0 &amp; 6 &amp; 1 \\ -1 &amp; 0 &amp; -3\end{array}\right]$$B=\left[\begin{array}{ccc}2 &amp; 1 &amp; 7 \\ 0 &amp; 2 &amp; -1 \\ -3 &amp; 4 &amp; 2\end{array}\right]$$C$$A+B+C=0$$$A+B+C=0,$$$$C=-A-B.$$\begin{align*}
C&amp;=-\begin{bmatrix}3 &amp; -1 &amp;…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Tue, 30 Jul 2024 07:29:12 +0000</pubDate>
        </item>
        <item>
            <title>Question 3, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p3</link>
            <description>Question 3, Exercise 2.2

Solutions of Question 3 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[\begin{array}{ccc}3 &amp; -1 &amp; 2 \\ 0 &amp; 6 &amp; 1 \\ -1 &amp; 0 &amp; -3\end{array}\right]$$B=\left[\begin{array}{ccc}2 &amp; 1 &amp; 7 \\ 0 &amp; 2 &amp; -1 \\ -3 &amp; 4 &amp; 2\end{array}\right]$$C$$A+B+C=0$$$A+B+C=0,$$$$C=-A-B.$$\begin{align*}
C&amp;=-\begin{bmatrix}3 &amp; -1 &amp;…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Tue, 30 Jul 2024 07:30:34 +0000</pubDate>
        </item>
        <item>
            <title>Question 4, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p4</link>
            <description>Question 4, Exercise 2.2

Solutions of Question 4 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A$\begin{align}\left[\begin{array}{cc} 2 &amp; 1 \\  3 &amp; 2 \end{array}\right]A\left[\begin{array}{cc} 1 &amp; 3 \\  2 &amp; 4 \end{array}\right]&amp;=\left[\begin{array}{cc} 1 &amp; 0 \\  0 &amp; 1 \end{array}\right]\end{align}$ B = \left[\begin{array}{cc} 2 &amp; 1 \\ 3…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Tue, 30 Jul 2024 07:29:39 +0000</pubDate>
        </item>
        <item>
            <title>Question 5, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p5</link>
            <description>Question 5, Exercise 2.2

Solutions of Question 5 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $X=\left[\begin{array}{lll}1 &amp; 2 &amp; 2 \\ 2 &amp; 1 &amp; 2 \\ 2 &amp; 2 &amp; 1\end{array}\right]$$X^{2}-4 X-5 I=0$\begin{align}L.H.S. &amp; =X^{2}-4 X-5 I \\
&amp;=\begin{bmatrix}
1 &amp; 2 &amp; 2 \\
2 &amp; 1 &amp; 2 \\
2 &amp; 2 &amp; 1
\end{bmatrix}
\begin{bmatrix}
1 &amp; 2 &amp; 2 \\
2 &amp; 1 &amp; 2…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 19 Aug 2024 16:11:12 +0000</pubDate>
        </item>
        <item>
            <title>Question 6, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p6</link>
            <description>Question 6, Exercise 2.2

Solutions of Question 6 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[\begin{array}{cc}2 &amp; 1 \\ 3 &amp; -3\end{array}\right]$$\alpha$$\beta$$A^{2}+\alpha I=\beta A$\begin{align}
&amp; A^{2}+\alpha I=\beta A\\
\implies &amp;\begin{bmatrix}
2 &amp; 1 \\
3 &amp; -3
\end{bmatrix}
\begin{bmatrix}
2 &amp; 1 \\
3 &amp; -3
\end{bmatrix}+\a…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 19 Aug 2024 16:24:24 +0000</pubDate>
        </item>
        <item>
            <title>Question 7, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p7</link>
            <description>Question 7, Exercise 2.2

Solutions of Question 7 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[\begin{array}{ll}x &amp; 0 \\ y &amp; 1\end{array}\right]$$n, A^{n}=\left[\begin{array}{cc}x^{n} &amp; 0 \\ \dfrac{y\left(x^{n}-1\right)}{x-1} &amp; 1\end{array}\right]$$$A = \begin{bmatrix} x &amp; 0 \\ y &amp; 1 \end{bmatrix}.$$$n = 1$\begin{align}A^1 =\beg…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 19 Aug 2024 16:42:50 +0000</pubDate>
        </item>
        <item>
            <title>Question 8, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p8</link>
            <description>Question 8, Exercise 2.2

Solutions of Question 8 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A$$B$$2 \times 3$$3 \times 2$$(A B)^{t}=B^{t} A^{t}$\( A \)\( B \)\( 2 \times 3 \)\( 3 \times 2 \)\begin{align*}
	A &amp;= \begin{bmatrix}
	a_{11} &amp; a_{12} &amp; a_{13} \\
	a_{21} &amp; a_{22} &amp; a_{23}
\end{bmatrix}\\
B &amp;= \begin{bmatrix}
	b_{11} &amp; b_{12}…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 19 Aug 2024 16:43:59 +0000</pubDate>
        </item>
        <item>
            <title>Question 9, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p9</link>
            <description>Question 9, Exercise 2.2

Solutions of Question 9 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A$$B$$3 \times 3$$(A+B)^{t}=A^{t}+B^{t}$\begin{align*}
A &amp;= \begin{pmatrix} 
a_{11} &amp; a_{12} &amp; a_{13} \\ 
a_{21} &amp; a_{22} &amp; a_{23} \\ 
a_{31} &amp; a_{32} &amp; a_{33} 
\end{pmatrix} \\
B &amp;= \begin{pmatrix} 
b_{11} &amp; b_{12} &amp; b_{13} \\ 
b_{21} &amp; b_{22…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 19 Aug 2024 16:44:43 +0000</pubDate>
        </item>
        <item>
            <title>Question 10, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p10</link>
            <description>Question 10, Exercise 2.2

Solutions of Question 10 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A$$B$$A B=B$$B A=A$$A^{2}+B^{2}$$$AB = B$$$$BA = A$$\begin{align*}
A^2 &amp;= AA\\
&amp; = A(BA)\\
&amp;=(AB)A\\
&amp;=BA\\
&amp;=A
\end{align*}\begin{align*}
B^2&amp;= BB \\
&amp;=B(AB)\\
&amp; = (BA)B\\
&amp;=AB\\
&amp;=B\end{align*}$$A^2 + B^2 = A + B$$$AB = B$$BA = A$$$A^2 + B…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 19 Aug 2024 16:47:00 +0000</pubDate>
        </item>
        <item>
            <title>Question 11, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p11</link>
            <description>Question 11, Exercise 2.2

Solutions of Question 11 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[a_{i j}\right]$$3 \times 3$$a_{i j}=i^{2}-j^{2}$$A$$A=\left[a_{i j}\right]$$a_{ij}=a+{ji}$$a_{ij}=-a_{ji}$$a_{i j}=i^{2}-j^{2}$\begin{align}
a_{ji} &amp; = j^2 -i^2 \\
&amp;= - (i^2 -j^2) \\
&amp;= - a_{ij}
\end{align}$a_{ij}=-a_{ji}$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 19 Aug 2024 16:55:20 +0000</pubDate>
        </item>
        <item>
            <title>Question 12, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p12</link>
            <description>Question 12, Exercise 2.2

Solutions of Question 12 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A$$\left(A^{n}\right)^{t}=\left(A^{t}\right)^{n}$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 19 Aug 2024 16:58:16 +0000</pubDate>
        </item>
        <item>
            <title>Question 13, Exercise 2.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-2-p13</link>
            <description>Question 13, Exercise 2.2

Solutions of Question 13 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $X$$Y$$2 X-Y=\left[\begin{array}{ccc}1 &amp; 6 &amp; -3 \\ 2 &amp; 1 &amp; 7\end{array}\right]$$X+3 Y=\left[\begin{array}{ccc}4 &amp; 3 &amp; 2 \\ 1 &amp; -3 &amp; 0\end{array}\right]$\begin{align*}
2X - Y = \begin{pmatrix} 1 &amp; 6 &amp; -3 \\ 2 &amp; 1 &amp; 7 \end{pmatrix} \cdots (i)\\…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 19 Aug 2024 16:58:35 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Exercise 2.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-3-p1</link>
            <description>Question 1, Exercise 2.3

Solutions of Question 1 of Exercise 2.3 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\left[\begin{array}{ccc}2 &amp; 3 &amp; 1 \\ 1 &amp; -1 &amp; 2 \\ 4 &amp; 1 &amp; 2\end{array}\right]$\begin{align*}
A &amp;= \left[\begin{array}{ccc}2 &amp; 3 &amp; 1 \\ 1 &amp; -1 &amp; 2 \\ 4 &amp; 1 &amp; 2\end{array}\right]\\
|A|&amp;=2(-2-2)-3(2-8)+1(1+4)\\
\implies |A|&amp;=-8+18+5\\
\implies |…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Fri, 23 Aug 2024 09:03:34 +0000</pubDate>
        </item>
        <item>
            <title>Question 2, Exercise 2.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-3-p2</link>
            <description>Question 2, Exercise 2.3

Solutions of Question 2 of Exercise 2.3 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\left[\begin{array}{lll}3 &amp; 2 &amp; 3 \\ 4 &amp; 5 &amp; 1 \\ 2 &amp; 1 &amp; 0\end{array}\right]$\(R_1\)\(a_{11} = 3\)\(a_{12} = 2\)\(a_{13} = 3\)\begin{align*}
A &amp;= \left[\begin{array}{ccc} 3 &amp; 2 &amp; 3 \\ 4 &amp; 5 &amp; 1 \\ 2 &amp; 1 &amp; 0 \end{array}\right]\\
&amp; A_{11} = (-1…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Fri, 23 Aug 2024 09:04:07 +0000</pubDate>
        </item>
        <item>
            <title>Question 3, Exercise 2.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-3-p3</link>
            <description>Question 3, Exercise 2.3

Solutions of Question 3 of Exercise 2.3 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\left[\begin{array}{ccc}3 &amp; 1 &amp; 2 \\ 2 &amp; 3 &amp; 1 \\ -4 &amp; 1 &amp; -3\end{array}\right]$\begin{align*}
A &amp;= \left[\begin{array}{ccc} 3 &amp; 1 &amp; 2 \\ 2 &amp; 3 &amp; 1 \\ -4 &amp; 1 &amp; -3\end{array}\right]\end{align*}\(3 \times 3\)\begin{align*}
|A| &amp;= 3(3 \cdot (-3) …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Fri, 23 Aug 2024 09:04:42 +0000</pubDate>
        </item>
        <item>
            <title>Question 4, Exercise 2.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-3-p4</link>
            <description>Question 4, Exercise 2.3

Solutions of Question 4 of Exercise 2.3 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\lambda$$\left[\begin{array}{lll}\lambda &amp; 1 &amp; 3 \\ 2 &amp; 1 &amp; 8 \\ 0 &amp; 3 &amp; 1\end{array}\right]$\begin{align*}
A &amp;= \left[\begin{array}{ccc}
\lambda &amp; 1 &amp; 3 \\
2 &amp; 1 &amp; 8 \\
0 &amp; 3 &amp; 1
\end{array}\right]\\
|A| &amp;= \lambda \cdot (-23) - 1 \cdot 2 + 3…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Fri, 23 Aug 2024 09:05:13 +0000</pubDate>
        </item>
        <item>
            <title>Question 5, Exercise 2.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-3-p5</link>
            <description>Question 5, Exercise 2.3

Solutions of Question 5 of Exercise 2.3 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\left[\begin{array}{ccc}1 &amp; -1 &amp; 1 \\ 2 &amp; 1 &amp; -1 \\ 1 &amp; -2 &amp; -1\end{array}\right]$\begin{align*}
A &amp;= \left[\begin{array}{ccc}
1 &amp; -1 &amp; 1 \\
2 &amp; 1 &amp; -1 \\
1 &amp; -2 &amp; -1
\end{array}\right]\\
|A|&amp;=  1 [-1 - 2] + 1 [-2 + 1] + 1 [-4 - 1] \\
&amp;= 1 \cd…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Fri, 23 Aug 2024 09:05:37 +0000</pubDate>
        </item>
        <item>
            <title>Question 6, Exercise 2.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-3-p6</link>
            <description>Question 6, Exercise 2.3

Solutions of Question 6 of Exercise 2.3 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[\begin{array}{ccc}2 &amp; 1 &amp; -3 \\ 0 &amp; 1 &amp; 0 \\ 2 &amp; 1 &amp; 6\end{array}\right]$$A^{-1}$$A A^{-1}=A^{-1} A=I_{3}$\begin{align*} A &amp;= \begin{bmatrix}
2 &amp; 1 &amp; -3 \\
0 &amp; 1 &amp; 0 \\
2 &amp; 1 &amp; 6
\end{bmatrix} \end{align*}$ A^{-1} $$ A $\begin{align*}
…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Fri, 23 Aug 2024 09:41:19 +0000</pubDate>
        </item>
        <item>
            <title>Question 7, Exercise 2.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-3-p7</link>
            <description>Question 7, Exercise 2.3

Solutions of Question 7 of Exercise 2.3 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $(A B)^{-1}=B^{-1} A^{-1}$$A=\left[\begin{array}{ll}2 &amp; 1 \\ 8 &amp; 6\end{array}\right]$$B=\left[\begin{array}{ll}3 &amp; 2 \\ 0 &amp; 2\end{array}\right]$\begin{align*}
A &amp;= \left[\begin{array}{ll}2 &amp; 1 \\ 8 &amp; 6\end{array}\right] \\	
|A|&amp; = 12 - 8 = 4\\	…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Fri, 23 Aug 2024 09:48:00 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Exercise 2.5</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-5-p1</link>
            <description>Question 1, Exercise 2.5

Solutions of Question 1 of Exercise 2.5 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\left[\begin{array}{ccc}1 &amp; 3 &amp; 5 \\ -6 &amp; 8 &amp; 3 \\ -4 &amp; 6 &amp; 5\end{array}\right]$\begin{align*}
&amp; \quad \left[\begin{array}{ccc}1 &amp; 3 &amp; 5 \\ -6 &amp; 8 &amp; 3 \\ -4 &amp; 6 &amp; 5\end{array}\right]\\
\sim &amp; \text{R}
\left[\begin{array}{ccc}
1 &amp; 3 &amp; 5 \\
0 &amp; …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:01:24 +0000</pubDate>
        </item>
        <item>
            <title>Question 2, Exercise 2.5</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-5-p2</link>
            <description>Question 2, Exercise 2.5

Solutions of Question 2 of Exercise 2.5 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\left[\begin{array}{ccc}5 &amp; 9 &amp; 3 \\ 3 &amp; -5 &amp; 6 \\ 2 &amp; 10 &amp; 6\end{array}\right]$\begin{align*}&amp;\quad\left[ \begin{array}{ccc}
5 &amp; 9 &amp; 3 \\ 
3 &amp; -5 &amp; 6 \\ 
2 &amp; 10 &amp; 6 
\end{array} \right]\\
\sim &amp; \text{R}\left[ \begin{array}{ccc}
1 &amp; \frac{9}{…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:01:56 +0000</pubDate>
        </item>
        <item>
            <title>Question 3, Exercise 2.5</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-5-p3</link>
            <description>Question 3, Exercise 2.5

Solutions of Question 3 of Exercise 2.5 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\left[\begin{array}{ccc}0 &amp; -1 &amp; -1 \\ -1 &amp; 3 &amp; 0 \\ 1 &amp; -1 &amp; 4\end{array}\right]$$A A^{-1}=A^{-1} A=I$\begin{align*}
A&amp;=\left[ \begin{array}{ccc}
0 &amp; -1 &amp; -1  \\ 
-1 &amp; 3 &amp; 0  \\ 
1 &amp; -1 &amp; 4 
\end{array} \right]\\
|A|&amp;=0+1(-4)-1(1-3)\\
&amp;=-4+3\…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:02:35 +0000</pubDate>
        </item>
        <item>
            <title>Question 2, Exercise 2.6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-6-p2</link>
            <description>Question 2, Exercise 2.6

Solutions of Question 2 of Exercise 2.6 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\lambda$$\lambda$$2 x_{1}-\lambda x_{2}+x_{3}=0$$2 x_{1}+3 x_{2}-x_{3}=0$$3 x_{1}-2 x_{2}+4 x_{3}=0$\begin{align*}
&amp;2 x_{1}-\lambda x_{2}+x_{3}=0 \cdots(i)\\
&amp;2 x_{1}+3 x_{2}-x_{3}=0\cdots(ii)\\
&amp;3 x_{1}-2 x_{2}+4 x_{3}=0\cdots(iii)\\
\end{ali…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:04:14 +0000</pubDate>
        </item>
        <item>
            <title>Question 3, Exercise 2.6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-6-p3</link>
            <description>Question 3, Exercise 2.6

Solutions of Question 3 of Exercise 2.6 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $2 x+3 y+4 z=2$$2 x+y+z=5$$3 x-2 y+z=-3$\begin{align*}
\begin{aligned}
2x + 3y + 4z &amp;= 2 \\
2x + y + z &amp;= 5 \\
3x - 2y + z &amp;= -3
\end{aligned}\end{align*}\begin{align*}
A_{b} &amp;=\quad \left[\begin{array}{cccc}
2 &amp; 3 &amp; 4 &amp; 2 \\
2 &amp; 1 &amp; 1 &amp; 5 \\
3…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:11:14 +0000</pubDate>
        </item>
        <item>
            <title>Question 4, Exercise 2.6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-6-p4</link>
            <description>Question 4, Exercise 2.6

Solutions of Question 4 of Exercise 2.6 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $2 x_{1}-x_{2}-x_{3}=2$$3 x_{1}-4 x_{2}+3 x_{3}=7$$4 x_{1}+2 x_{2}-5 x_{3}=10$\begin{align*}
2x_1 - x_2 - x_3 &amp;= 2, \\
3x_1 - 4x_2 + 3x_3 &amp;= 7, \\
4x_1 + 2x_2 - 5x_3 &amp;= 10,
\end{align*}\begin{align*}	
A_b &amp;= \begin{bmatrix}
2 &amp; -1 &amp; -1 &amp; : &amp; 2 …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:11:42 +0000</pubDate>
        </item>
        <item>
            <title>Question 5, Exercise 2.6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-6-p5</link>
            <description>Question 5, Exercise 2.6

Solutions of Question 5 of Exercise 2.6 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $x_{1}+x_{2}+2 x_{3}=8$$-x_{1}-2 x_{2}+3 x_{3}=1$$3 x_{1}-7 x_{2}+4 x_{3}=10$$A X=B$\begin{align*}
&amp;A = \begin{bmatrix}
1 &amp; 1 &amp; 2 \\
-1 &amp; -2 &amp; 3 \\
3 &amp; -7 &amp; 4
\end{bmatrix}, \quad
X = \begin{bmatrix}
x_1 \\
x_2 \\
x_3
\end{bmatrix}, \quad
B = \…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:12:33 +0000</pubDate>
        </item>
        <item>
            <title>Question 6, Exercise 2.6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-6-p6</link>
            <description>Question 6, Exercise 2.6

Solutions of Question 6 of Exercise 2.6 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $5 x+3 y+z=6$$2 x+y+3 z=19$$x+2 y+4 z=25$\begin{align*}
A &amp;= \begin{bmatrix}
5 &amp; 3 &amp; 1 \\
2 &amp; 1 &amp; 3 \\
1 &amp; 2 &amp; 4
\end{bmatrix}, \quad
X = \begin{bmatrix}
x \\
y \\
z
\end{bmatrix}, \quad
B = \begin{bmatrix}
6 \\
19 \\
25
\end{bmatrix}
\end{alig…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:13:00 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 and 10, Exercise 2.6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/ex2-6-p8</link>
            <description>Question 9 and 10, Exercise 2.6

Solutions of Question 9 and 10 of Exercise 2.6 of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $2 x-y+3 z=\alpha ; 3 x+y-5 z=\beta ;-5 x-5 y+21 z=\gamma$$\gamma \neq 2 \alpha-3 \beta$$2$$2$$3$$3$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:13:56 +0000</pubDate>
        </item>
        <item>
            <title>Question 2 and 3, Review Exercise</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit02/re-ex-p2</link>
            <description>Question 2 and 3, Review Exercise

Solutions of Question 2 and 3 of Review Exercise of Unit 02: Matrices and Determinants. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $A=\left[\begin{array}{ccc}1 &amp; 2 &amp; 0 \\ -3 &amp; 4 &amp; 9 \\ 2 &amp; 1 &amp; 6\end{array}\right]$$A_{13}, A_{23}$$A_{33}$$|A|$\begin{align*}
A&amp;=\left[\begin{array}{ccc}1 &amp; 2 &amp; 0 \\ -3 &amp; 4 &amp; 9 \\ 2 &amp; 1 &amp; 6\end{array}\right]\\
A_{13} &amp;= (-1)^{…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 04 Sep 2024 03:15:23 +0000</pubDate>
        </item>
    </channel>
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